Brought up on Craigmore Station in the South Island of New Zealand Forbes worked as a shepherd in the early part of his career. He then trained in Agricultural Economics at Lincoln University in New Zealand where he was student president in 1984. He went to Oxford as a Rhodes Scholar in 1985. After some time at Goldman Sachs he completed an MBA at Harvard Business School in 1992. Forbes worked as a credit trader at Merrill Lynch from 1992 to 1999 where he headed a convertibles trading desk. He then led financial information publisher Credit Market Analysis which was acquired by Chicago Mercantile Exchange. Forbes returned full time to farming in 2005 to live on and manage Craigmore Station – a sheep, beef and deer property farmed by the Elworthy family since 1864.